Why does this virtual destructor trigger an unresolved external?

Question

Consider the following:

In X.h:

class X
{
    X();
    virtual ~X();
};

X.cpp:

#inclu         


        

Answer 1

These aren't a complete program yet (or even a complete DLL). When you are getting the error, you are actually being helped, because X is unusable without a definition for ~X()

All it means is that this specific compiler instance needed a definition for it in some cases. Even if it compiles, it doesn't do anything.